Filter press method and apparatus

ABSTRACT

A filter press with a plurality of filter plates mounted in side-by-side relationship and method and apparatus for cleaning the cake from the plates. The cake is formed upon the opposed side faces of the plates, and each of the side faces is covered by fabric. The fabric is flexed away from the plate by pressurized air which is introduced between the plate and the fabric to remove the cakes. Each plate has an operating unit formed by an air valve for controlling airflow into the plate, a rotatably mounted valve-actuator arm and a pair of abutment members adjacent the opposed top edges of the plate. When removing the cakes the plates are moved sequentially, away from the stack and laterally in the press. During the initial movement of each plate one of the abutment members on an adjacent plate engages and swings the actuator arm of the moving plate so as to open its valve, and the cakes are removed. The cleaned plate is then moved on, and an abutment member on the opposed adjacent plate engages the actuator arm for closing the valve.

United States Patent 72] lnventor William L. Fismer Verona, NJ. 21 Appl.No. 31,174 [22] Filed Apr. 23, 1970 [45] Patented Jan. 11, 1972 [73]Assignee T. Shriver & Company, Inc.

Harrison, N .J

[54] FILTER PRESS METHOD AND APPARATUS 10 Claims, 4 Drawing Figs.

[52] U.S.Cl 210/81, 210/225 [51] Int. Cl 801d 23/24 [50] Field of Search210/81, 82, 224-231, 141, 142, 393, 410; 100/198, 199

[56] References Cited UNITED STATES PATENTS 3,347,383 11/1965 Augerot210/225 3,390,772 7/1968 Juhasz 210/225 X Primary Examiner-Samih N.Zaharna Assistant Examiner-T. A. Granger Attorney-Curtis, Morris &Safford ABSTRACT: A filter press with a plurality of filter platesmounted in side-by-side relationship and method and apparatus forcleaning the cake from the plates. The cake is formed upon the opposedside faces ofthe plates, and each of the side faces is covered byfabric. The fabric is flexed away from the plate by pressurized airwhich is introduced between the plate and the fabric to remove thecakes. Each plate has an operating unit formed by an air valve forcontrolling airflow into the plate, a rotatably mounted valve-actuatorarm and a pair of abutment members adjacent the opposed top edges of theplate. When removing the cakes the plates are moved sequentially, awayfrom the stack and laterally in the press During the initial movementofeach plate one of the abutment members on an adjacent plate engagesand swings the actuator arm of the moving plate so as to open its valve,and the cakes are removed. The cleaned plate is then moved on, and anabutment member on the opposed adjacent plate engages the actuator armfor closing the valve.

PATENTEDJANI 1 1972 3163374.,

SHEET 1 UF 2 Flltrofe Compressed Air Compressed Alr WILLIAM L. FISMER Afornevs PATENTED JAN 1 I972 SHEET 2 [IF 2 WILLIAM FISMER BY M, I

Attornevs FELTER PRESS METHOD AND APPARATUS This invention relates toimprovements in filter presses, and more particularly to methods andapparatus for controlling airflow through the filter plates duringremoval of the filter cake and cleaning of the filter fabric.

Filter presses are generally used to remove solid particles fromliquids. One such press is disclosed in Augerot, US. Pat. No. 3,347,383,which disclosure is incorporated herein by reference. Substantially,that patent describes filter presses having filter plates with opposedfilter cloth surfaces arranged in side-by-side relation for filteringsolids containing material across the filter plate cloths and fordischarging the filtrate from the zone between the cloths on each plate.As the filtration process continues filter cakes form on the filtercloth surface on each side of each of the plates. The cakes are removedby charging the zone between each cloth and its plate with pressurizedair to flex the cloth away from the plate and detach the cake. For thisprocess to be performed the plates must be separated and shifted in thepress so that adjacent cloths are free to flex.

It is an object of this invention to provide a method and apparatuswhich automatically controls the fiow of air to the filter plates duringthe cleaning operation. It is another object to provide for sequentialcleaning of filter plates in a filter press. A further object is tosynchronize the shifting of plates during a cleaning process utilizing apneumatic cake discharge or cleaning system. Another object is toprovide a completely automatic filtering and cleaning process. It is afurther object of the invention to provide a relatively simple andinexpensive apparatus for cleaning filter plates having flexible fabricsidewalls.

The construction of the preferred embodiment as well as further objectsand advantages thereof will become further apparent from the followingspecification when considered in conjunction with the accompanyingdrawings wherein:

FIG. 1 is a schematic illustration of the filter press of the presentinvention with the sequential valve system removed;

FIG. 2 is a sectional side view of one of the plates in the filter pressof FIG. 1;

FIG. 3 is a top plan view with parts broken away of the press of FIG. 1,during the cleaning cycle; and

FIG. 4 is a view taken along line 4-4 of FIG. 3 of the top of an endfilter plate.

Referring now to the drawings, and in particular to FIG. 1 there isschematically illustrated a filter press having a fixed head H mountedon a supporting frame S which carries a series of filter plates F inside-by-side relation and which can be clamped together by means of amovable head P also carried by the frame. Head P is actuated by means ofa hydraulic or pneumatic jack J to press and hold the plates in tightface-toface and leakproof relation. The plates are separated during thecleaning process either manually, after the retraction of movable headP, or preferably, by means of an automatic plate shifting device of aknown type.

The filter plates used in the preferred embodiment of this invention aresimilar to those described in US. Pat. No. 3,347,383 and one such plateis illustrated in section in FIG. 2. This plate is described in somedetail herein to facilitate a full understanding of the presentinvention.

Each plate F includes an outer frame I and an inner partition plate 12which are integrally cast. Plate 12 has a plurality of communicatinggrooves 14 and 16 on its opposite faces 18 and 28 respectively. Internalperipheral grooves 22 and 24 are machines in the sides of frame It) onopposite sides of partition plate 12 to receive screens 26 and 28 forsupporting filter clothes 30 and 32 respectively. As illustrated, thefilter cloths have ropelike gaskets 34 and 36 sewn in their edges andthey are of such dimensions that they are snugly received and held ingrooves 22 and 24. Thus, the cloths are held tightly so that the airpressure used for discharging the cake will not blow the cloths out ofthe frame. The plate and filter cloths are generally rectangularlyshaped and each plate frame includes a pair of inlet ports 40 and a pairof outlet ports 42. These ports are located in diagonally opposed upperand lower corners of the plate and thus only one of each type is seen inthe sectional view of FIG. 2.

Inlet ports 40 are formed in cast portions of less width than frame 10so that liquid can readily flow from the inlet pipe (FIG. 1) throughports 40 and against the outer surfaces of cloths 30 and 32 into grooves14 and 16 of plate 12. Discharge ports 42 are formed in cast portions ofapproximately the same width as frame 10 and thus the adjacent dischargepassages in the various plates form a continuous discharge conduit.Grooves I4 and 16 communicate with discharge passages 42 for removal ofthe filtered liquid from between cloths 30 and 32.

Solids in the liquid form in layers or cakes on the cloths. When therecesses between filter plates F are filled with solids, or when theflow rate is reduced to the minimum rate, valves (not shown) controllingthe fluid flow are closed to stop the filtering operation. The platesare sequentially moved apart manually or automatically, starting at theplate at the right in FIG. I. Compressed air is then introduced throughthe inlet pipe 44 (FIG. 2) of that plate which is connected with aninverted T-passageway 46 for supplying air pressure behind filter cloths30 and 32. The introduction of compressed air in this manner into plates10 causes cloths 30 and 32 to bow or billow outwardly as shown in brokenlines in FIG. 2, thereby peeling or stripping the filter cake from thecloths.

The apparatus illustrated in FIGS. 3 and 4 is provided to automaticallycontrol the airflow into each of the plates F during the cleaningprocess. As each plate is moved laterally in the press, compressed airis supplied to it and the air is then shut off at the end of the lateralmovement.

Particularly, in FIG. 3, six filter plates 50, 52, 54, 56, 58 and 60 arepartially illustrated as they would appear in a top view of filter pressP during the filter cleaning process. The plates are moved sequentiallyin the direction indicated by the arrow T, one at a time, and theintroduction of air into each plate occurs as the plate is beingshifted. Accordingly, in the situation illustrated, plates 60 and 58have been cleaned, plate 56 is in the process of being cleaned and theremaining plates are not yet cleaned.

A control unit is provided on each plate F to control the flow ofcompressed air from a source 71 thereof (which is representedschematically) to pipe 44 of each of plates F. Control unit 70 includesball valve 72 and valve linkage actuator arm 74 operatively connected tothe valve. The control system 70 is the same for each plate and thusonly one such system is described in detail.

Actuator arm 74 is generally 5 shaped and is pivotally mounted at itscenter 75 on baseplate 76. Baseplate 76 is mounted on plate F by a pairof hold down bolts 78 and is leveled by four jackscrews 80 with jam nuts82. At one end of baseplate 76 a spring loaded pawl 84 is provided whichextends beyond the right side of plate F in the direction of travelthereof. Pawl 84 is wedge shaped and pivotally mounted on axis 85whereby it may be depressed through the aperture 86 in plate 76. As seenin FIG. 3, pawl 84 on plate 52 is engaged with one leg 77 of arm 74 ofadjacent plate 54 and serves to effect rotation of arm 74 as plate 54 ismoved in the direction of travel.

Baseplate 76 is also provided with a stop member 88 adjacent the side ofplate F opposite from pawl 84. This stop member is located between thetwo hold down bolts 78 and engages the other leg 79 of actuator arm 74.As the lateral shifting movement continues, leg 79 of the actuator armon plate 56 will engage stop 88 of adjacent plate 58 to counter rotatearm 74. In addition, as plate 55 moves to its final position adjacentplate 58, leg 77 of the actuator arm on plate 58 will depress wedgeshaped pawl 84 on plate 56 until it has passed completely over the pawl.Due to the spring loading of pawl 84, it will then move back to itsnormal configuration and in this manner be prepared for the nextcleaning operation.

Rotation of valve actuator arm 74, as described above, controls airflowthrough ball valve 72. Crankarm 90 is fixed to arm 77 and connecting rod94 is rotatably connected at one end to crank 90 at a point 92 off itscenter of rotation. The opposed end of connecting rod 94 is pivotallyattached by connector link 96 to the operating crank arm 98 of valve 72.[n this manner the angular motion of arm 74 is transmitted by connectingrod 94 to crank 98 of valve 72. Crank 98 is secured to the stem of valve72 and as actuator arm 74 is rotated by engagement with an adjacent pawl84, connecting rod 94 imparts thismotion upon crank 98 causing the valveto open and admit a pulse of compressed air. Conversely, as arm 74 isrotated to its original position by engagement with an adjacent stop 88,the connecting rod pushes valve crank arm 98 to close valve 72 and shutoff the air pulse.

The end of connecting rod 94 fixed to link 96 is threaded, and extendsthrough a bore in the link. A pair of nuts 97 threaded on rod 94 onopposite sides of link 96 permit axial adjustment of rod 94 and thespecific angular relation between the various elements.

The intermediate plates in press P each have the same actuator system70, however, the plates at each end of the row are slightly modifiedsince they do not have an adjacent plate on each side; Thus the firstplate cleaned, plate 60, does not require pawl 86 to actuate an adjacentplate and therefore the pawl is eliminated.

Since there is no plate to the left of head liner plate 50, i.e., thelast plate to be cleaned, this plate does not require a stop member andin addition, cannot have an actuator arm since there is no adjacent pawlto engage with. Accordingly, the next to last plate to be cleaned, plate52, utilizes an additional crank arm 100 on its valve 72 so that themotion of its connecting rod 94 may also be utilized to control airflowinto plate 50. This result is achieved by providing a second valve 102having crank arm 104 connected to the stem of the valve for operativecontrol thereof. in addition, second connecting rod 106 is pivotallysecured at each end to cranks 100 and 104, respectively. As seen in FIG.4 these pivotal connections are formed by connector links 108 and nuts110 threaded on rod 106 in a manner similar to that described above withrespect to link 96. in this manner, as valve 72 on plate 52 is openedand closed by its arm 74, valve 102 will be similarly opened and closed.

Air flows through valve 102 through fitting 112 and flexible hose 114 toa second elbow fitting 116 which communicates with grooves 14 and 16 ina manner similar to that discussed above with respect to pipe 44.Accordingly, head liner plate 50 is cleaned simultaneously with plate 52as the latter is moved laterally in press P. In addition it is notedthat since plate 50 does not have an actuator arm, plate 52 also doesnot require a stop 88.

It is thus seen that as a typical plate, i.e., plate 56, is initiallymoved in the cleaning process, its actuator arm 74 contacts the verticalsurface 87 of pawl 84 on plate 54, causing arm 74 to rotatecounterclockwise. Arm 74 is rotated during its lateral movement 'farenough to slip by pawl 84 and cause connecting rod 94 to rotate crank 98and open valve 72, thus permitting airflow through pipe 44 betweencloths 30 and 32. Airflow continues until plate 56 is moved far enoughto the right so that leg 79 of arm 74 engages stop 88 on plate 58. Asplate 56 moves further to the right, the edge of leg 79 slides againststop 88 and causes arm 74 to rotate clockwise, thus shutting off theflow of air to plate 56. When the pawl 84 touches ac tuator arm 74 onplate 58, the arm rides up over inclined top surface 89 of the pawl anddepresses it against its spring load. Thus arm 74 passes over the pawland then the spring returns the pawl to its original position.

The above description of the invention is intended to be illustrativeonly, and various changes and modifications in the embodiments describedmay occur to those skilled in the art. These may be made withoutdeparting from the scope of the invention and thus it should be apparentthat the invention is not limited to the specific embodimentsillustrated in the drawings.

What is claimed is:

1. In a sequentially operated valve control system for use in carryingon a filter plate cleaning process wherein each plate has a pair offlexible fabric covers positioned respectively upon its sidewalls and ismoved from a first position adjacent other plates in the filter platestack to a second position in which it is separated from the otherplates and the plate-is cleaned and thence to a third position, thecombination of separate valve means for each plate for controlling theentrance of pressurized air intothe zones between the plate and itsflexible fabric covers, valve actuator means associated with each ofsaid valve means, and means mounted to move with each plate and tosequentially operate the valve actuator means of adjacent plates to openand close their associated valve means during movement from said firstto second positions.

2. A sequentially operated valve control system for use in carrying on afilter plate cleaning process wherein each plate has a pair of flexiblefabric covers positioned respectively upon its sidewalls and is movedfrom a first position adjacent other plates in the filter plate stack toa second position in which it is separated from the other plates and theplate is cleaned and thence to a third position, comprising a pluralityof filter plates, an air valve mounted upon each of said plates adaptedto control the flow of pressurized air to its plate between each of thefabric covers and the adjacent sidewalls, rotatable actuator means oneach of said plates for sequentially operating said valves, saidapparatus including means for rotating said actuator means to open thevalve for each plate when that plate is moved from said first positionto said second position, said apparatus also including means to rotatesaid actuator means to close the valve of each plate while in saidsecond position prior to movement of the next adjacent plate in thestock from said first position.

3. An apparatus for controlling airflow to the interior of filter plateshaving flexible fabric sidewalls defining first and second sides, duringthe lateral movement of the plates in a filter cleaning process,comprising, valve means mounted on each plate for controlling theintroduction of air into its associated plate, valve control apparatuson each of said plates including, a rotatably mounted actuator arm,means operatively connected to said valve and said arm for opening andclosing the valve in response to arm rotation, abutment means foreffecting rotation of the actuator arm on the filter plate adjacent aplates first side and stop means for efi'ecting counter rotation of theactuator arm on the filter plate adjacent a plates second side wherebyas a plate is moved laterally in the cleaning process its actuator armis initially rotated by the abutment means on the filter plate adjacentits second side to open the valve and at the end of its movement itsactuator arm is counter rotated by the stop means on the filter plateadjacent its first side to close the valve.

4. The apparatus as defined in claim 3 wherein said actuator arm forms asubstantially S-shaped member rotatably mounted at its center on itsassociated filter plate and said abutment means comprises a springloaded pawl extending beyond the first side of the plate on which it ismounted whereby, as each of said plates comes to rest at the end of saidlateral movement said pawl is contacted by the first leg of the actuatormounted on the plate adjacent its first side and depressed to permit theleg to pass thereover.

5. The control system of claim 4 wherein said valve means comprises aball valve having rotatable control arm and said actuator arm includes aconnecting rod pivotably connected at one end to said arm eccentricallyof its center of rotation and pivotably connected at its other end tosaid valve control arm whereby rotation of the actuator arm effectsrotation of the valve control arm to open and close the valve.

6. An automatic valve control system for use on filter plates, havingflexible fabric filters on opposed sides thereof, during a cleaningprocess wherein a plurality of such plates are positioned adjacent eachother in a starting position and individual plates are moved laterallyfrom the starting position to a final position while air is introducedbetween the fabric filters to flex the filters and remove filtrate cakestherefrom, comprising, an air valve on each of said filter plates, anactuator means rotatably mounted on each of said filter plates foropening the valve on initiation of lateral movement, means on one sideof each of said filter plates for engaging the actuator means of thefilter plate adjacent said one side whereby as said adjacent plate ismoved laterally said actuator means is rotated to open said valve andadmit air between the fabric filters, and stop means on the other sideof each of said filter plates for contacting the actuator means of thefilter plate adjacent said other side at the end of its lateral movementwhereby said actuator means is rotated in an opposite direction to closethe valve.

7. An automatic valve control system for use on a plurality of adjacentfilter plates having flexible fabric filters, in a cleaning processwherein each plate is moved laterally and charged with air through acontrol valve thereon during movement to flex the fabric filters andremove filtrate cakes therefrom, comprising, a generally S-shapedactuator member rotatably mounted at its center on each of said platesand defining an upper and lower arm, a pivoted pawl member mounted oneach plate in a location wherein it is adapted to be engaged by theupper arm of the actuator on the filter plate immediately to its right,a stop means mounted on each of said plates in a position wherein it isadapted to be engaged by the lower arm of the actuator on the filterplate immediately to its left and means operatively connected betweensaid actuator and said valve for operating said valve in response topivotal movement of the actuator arm, wherein the initial lateralmovement of a plate during the cleaning process causes the upper arm ofits associated actuator means to contact the pawl on the immediatelyadjacent plate to its left, to pivot the actuator and open the valve andcontinued movement of the plate causes the lower arm of its actuator tocontact the stop means on the immediately adjacent plate to its right,to close the valve.

8. A method of cleaning filter plates having flexible fabric filters onopposed sides thereof, comprising, the steps of moving said platessequentially from a first to a second position in a filter press,introducing a flow of compressed air into a plate to be cleaned betweenits fabric sides, on the initiation of movement thereof, and shuttingoff said flow of compressed air when said plate being cleaned reachessaid second position.

9. The method as described in claim 8 including the step of maintainingsaid flow of air during movement of said plates from said first tosecond positions.

10. A method of cleaning filter plates having flexible fabric filters onopposed sides thereof, comprising, the steps of. moving said platessequentially from a first to a second position in a filter press,automatically and sequentially operating a valve member on each of saidplates for introducing a flow of compressed air from a source thereof,into said plates between said fabric filters upon initiation of movementof an individual plate away from said first position, maintaining saidvalve in an open position during movement of said individual platetowards said second position, and automatically operating said valve toshut off said flow of compressed air as said individual plate moves intosaid second position.

2. A sequentially operated valve control system for use in carrying on afilter plate cleaning process wherein each plate has a pair of flexiblefabric covers positioned respectively upon its sidewalls and is movedfrom a first position adjacent other plates in the filter plate stack toa second position in which it is separated from the other plates and theplate is cleaned and thence to a third position, comprising a pluralityof filter plates, an air valve mounted upon each of said plates adaptedto control the flow of pressurized air to its plate between each of thefabric covers and the adjacent sidewalls, rotatable actuator means oneach of said plates for sequentially operating said valves, saidapparatus including means for rotating said actuator means to open thevalve for each plate when that plate is moved from said first positionto said second position, said appAratus also including means to rotatesaid actuator means to close the valve of each plate while in saidsecond position prior to movement of the next adjacent plate in thestock from said first position.
 3. An apparatus for controlling airflowto the interior of filter plates having flexible fabric sidewallsdefining first and second sides, during the lateral movement of theplates in a filter cleaning process, comprising, valve means mounted oneach plate for controlling the introduction of air into its associatedplate, valve control apparatus on each of said plates including, arotatably mounted actuator arm, means operatively connected to saidvalve and said arm for opening and closing the valve in response to armrotation, abutment means for effecting rotation of the actuator arm onthe filter plate adjacent a plate''s first side and stop means foreffecting counter rotation of the actuator arm on the filter plateadjacent a plate''s second side whereby as a plate is moved laterally inthe cleaning process its actuator arm is initially rotated by theabutment means on the filter plate adjacent its second side to open thevalve and at the end of its movement its actuator arm is counter rotatedby the stop means on the filter plate adjacent its first side to closethe valve.
 4. The apparatus as defined in claim 3 wherein said actuatorarm forms a substantially S-shaped member rotatably mounted at itscenter on its associated filter plate and said abutment means comprisesa spring loaded pawl extending beyond the first side of the plate onwhich it is mounted whereby, as each of said plates comes to rest at theend of said lateral movement said pawl is contacted by the first leg ofthe actuator mounted on the plate adjacent its first side and depressedto permit the leg to pass thereover.
 5. The control system of claim 4wherein said valve means comprises a ball valve having rotatable controlarm and said actuator arm includes a connecting rod pivotably connectedat one end to said arm eccentrically of its center of rotation andpivotably connected at its other end to said valve control arm wherebyrotation of the actuator arm effects rotation of the valve control armto open and close the valve.
 6. An automatic valve control system foruse on filter plates, having flexible fabric filters on opposed sidesthereof, during a cleaning process wherein a plurality of such platesare positioned adjacent each other in a starting position and individualplates are moved laterally from the starting position to a finalposition while air is introduced between the fabric filters to flex thefilters and remove filtrate cakes therefrom, comprising, an air valve oneach of said filter plates, an actuator means rotatably mounted on eachof said filter plates for opening the valve on initiation of lateralmovement, means on one side of each of said filter plates for engagingthe actuator means of the filter plate adjacent said one side whereby assaid adjacent plate is moved laterally said actuator means is rotated toopen said valve and admit air between the fabric filters, and stop meanson the other side of each of said filter plates for contacting theactuator means of the filter plate adjacent said other side at the endof its lateral movement whereby said actuator means is rotated in anopposite direction to close the valve.
 7. An automatic valve controlsystem for use on a plurality of adjacent filter plates having flexiblefabric filters, in a cleaning process wherein each plate is movedlaterally and charged with air through a control valve thereon duringmovement to flex the fabric filters and remove filtrate cakes therefrom,comprising, a generally S-shaped actuator member rotatably mounted atits center on each of said plates and defining an upper and lower arm, apivoted pawl member mounted on each plate in a location wherein it isadapted to be engaged by the upper arm of the actuator on the filterplate immediately to its right, a stop means mounted on each oF saidplates in a position wherein it is adapted to be engaged by the lowerarm of the actuator on the filter plate immediately to its left andmeans operatively connected between said actuator and said valve foroperating said valve in response to pivotal movement of the actuatorarm, wherein the initial lateral movement of a plate during the cleaningprocess causes the upper arm of its associated actuator means to contactthe pawl on the immediately adjacent plate to its left, to pivot theactuator and open the valve and continued movement of the plate causesthe lower arm of its actuator to contact the stop means on theimmediately adjacent plate to its right, to close the valve.
 8. A methodof cleaning filter plates having flexible fabric filters on opposedsides thereof, comprising, the steps of moving said plates sequentiallyfrom a first to a second position in a filter press, introducing a flowof compressed air into a plate to be cleaned between its fabric sides,on the initiation of movement thereof, and shutting off said flow ofcompressed air when said plate being cleaned reaches said secondposition.
 9. The method as described in claim 8 including the step ofmaintaining said flow of air during movement of said plates from saidfirst to second positions.
 10. A method of cleaning filter plates havingflexible fabric filters on opposed sides thereof, comprising, the stepsof, moving said plates sequentially from a first to a second position ina filter press, automatically and sequentially operating a valve memberon each of said plates for introducing a flow of compressed air from asource thereof, into said plates between said fabric filters uponinitiation of movement of an individual plate away from said firstposition, maintaining said valve in an open position during movement ofsaid individual plate towards said second position, and automaticallyoperating said valve to shut off said flow of compressed air as saidindividual plate moves into said second position.